greenhouse monitoring using zigbee1

8/19/2019 Greenhouse Monitoring Using Zigbee1

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GREENHOUSE MONITORING USING ZIGBEE

ABSTRACT

Monitoring and control of greenhouse environment play an important role ingreenhouse production and management. To monitor the greenhouse environment

parameters effectively, it is necessary to design a measurement and control system.

The aim of this project is to monitor the conditions in green house by using sensor nodes which collect the signals from the humidity sensor, soil moisture sensor andcontrol the actuators, and transmit the data through the wireless RF transceiver; themaster node receives the data through the RF transceiver .

All the parameters can be measured by using ATM ! "#s$% microcontroller transmitted to far distance by using wireless communication system called &igbee. .Result shows that the system is practical and reliable, and has wide application in thefuture

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INTRODUCTION

'e live in a world where everything can be controlled and operated

automatically, but there are still a few important sectors in our country where

automation has not been adopted or not been put to a full(fledged use, perhaps

because of several reasons one such reason is cost. )ne such field is that of

agriculture. Agriculture has been one of the primary occupations of man since earlycivili*ations and even today manual interventions in farming are inevitable.

+reenhouses form an important part of the agriculture and horticulture sectors in our

country as they can be used to grow plants under controlled climatic conditions for

optimum produce . Automating a greenhouse envisages monitoring and controlling

of the climatic parameters which directly or indirectly govern the plant growth and

hence their produce. Automation is process control of industrial machinery and

processes, thereby replacing human operators.

CURRENT SCENARIO:

+reenhouses in ndia are being deployed in the high(altitude regions where the

sub( *ero temperature up to (- / 0 ma1es any 1ind of plantation almost impossible

and in arid regions where conditions for plant growth are hostile. The e2isting set(ups

primarily are3

MANUAL SET-UP:

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This set(up involves visual inspection of the plant growth, manual irrigation of

plants, turning )4 and )FF the temperature controllers, manual spraying of the

fertili*ers and pesticides. t is time consuming, vulnerable to human error and

hence less accurate and unreliable.

PARTIALLY AUTOMATED SET-UP :

This set(up is a combination of manual supervision and partial automation

and is similar to manual set(up in most respects but it reduces the labor

involved in terms of

irrigating the set(up .

FULLY- AUTOMATED:

This is a sophisticated set(up which is well e5uipped to react to most of the climatic

changes occurring inside the greenhouse. t wor1s on a feedbac1 system which helps it

to respond to the e2ternal stimuli efficiently. Although this set(up overcomes the

problems caused due to human errors it is not completely automated and e2pensive.

3.BLOCK DIAGRAM OF THE PROJECT

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Fig 3.1-BLOCK DIAGRAM

4.Power Supply

Block Diagram:

There are many types of power supply. Most are designed to convert high voltage A0

mains electricity to a suitable low voltage supply for electronics circuits and other

devices. A power supply can by bro1en down into a series of bloc1s, each of which

performs a particular function.

For e2ample a $6 regulated supply3

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FIG 4.1

ach of the bloc1s is described in more detail below3

• Transformer ( steps down high voltage A0 mains to low voltage A0.

• Rectifier ( converts A0 to 70, but the 70 output is varying.

• 8moothing ( smoothes the 70 from varying greatly to a small ripple.

• Regulator ( eliminates ripple by setting 70 output to a fi2ed voltage.

9ower supplies made from these bloc1s are described below with a circuit diagram and a

graph of their output3

• Transformer only

• Transformer : Rectifier

• Transformer : Rectifier : 8moothing

• Transformer : Rectifier : 8moothing : Regulator

Dual Supplies:

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8ome electronic circuits re5uire a power supply with positive and negative outputs as

well as *ero volts 6#6 supply has :#6, 6 and (#6outputs .

Transformer only:

The low vol !"# AC output is suitable for lamps, heaters and special A0 motors. t is

$o suitable for electronic circuits unless they include a rectifier and a smoothing

capacitor.

Transformer + Rectifier:

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The v!%&'$" DC output is suitable for lamps, heaters and standard motors. t is $o

suitable for electronic circuits unless they include a smoothing capacitor.

Transformer + Rectifier + Smoothing:

The ()oo * DC output has a small ripple. t is suitable for most electronic circuits.

Transformer + Rectifier + Smoothing + Regulator:

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The %#"+l! #, DC output is very smooth with no ripple. t is suitable for all electronic

circuits.

Transformer:

Transformer circuit symbol

Transformers convert A0 electricity from one voltage to another with little loss of

power. Transformers wor1 only with A0 and this is one of the reasons why mains

electricity is A0.

8tep(up transformers increase voltage, step(down transformers reduce voltage. Most

power supplies use a step(down transformer to reduce the dangerously high mains

voltage %? 6 in @ < to a safer low voltage.Page9

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The input coil is called the %')!%& and the output coil is called the (# o$,!%& . There is

no electrical connection between the two coils, instead they are lin1ed by an alternating

magnetic field created in the soft(iron core of the transformer. The two lines in the

middle of the circuit symbol represent the core.

Transformers waste very little power so the power out is almost< e5ual to the power in.

4ote that as voltage is stepped down current is stepped up.

The ratio of the number of turns on each coil, called the +%$( %! 'o, determines the ratio

of the voltages. A step(down transformer has a large number of turns on its primary

input< coil which is connected to the high voltage mains supply, and a small number of

turns on its secondary output< coil to give a low output voltage.

Rectifier:

There are several ways of connecting diodes to ma1e a rectifier to convert A0 to 70.The bridge rectifier is the most important and it produces /+ll-w!v#

varying 70. A full(wave rectifier can also be made from just two diodes if a centre(tap

transformer is used, but this method is rarely used now that diodes are cheaper. A

single diode can be used as a rectifier but it only uses the positive :< parts of the A0

wave to produce *!l/-w!v# varying 70.

Bridge rectifier:

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A bridge rectifier can be made using four individual diodes, but it is also available in

special pac1ages containing the four diodes re5uired. t is called a full(wave rectifier

because it uses the entire A0 wave both positive and negative sections


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Bridge re !i"ier

Alternate pairs of diodes conduct, changing

over

the connections so the alternating

directions of

A0 isconverted to one direction of 70 .

Ou!pu!# "ull-w$%e %$ryi&g DC

using all the A0 wave<

Single diode rectifier:

A single diode can be used as a rectifier but this produces *!l/-w!v# varying 70 which

has gaps when the A0 is negative. t is hard to smooth this sufficiently well to supply

electronic circuits unless they re5uire a very small current so the smoothing capacitor

does not significantly discharge during the gaps. 9lease see the 7iodes page for some

e2amples of rectifier diodes.

Si&gle diode re !i"ier Ou!pu!# '$l"-w$%e %$ryi&g DC

(using only half the AC wave)

Smoothing:

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8moothing is performed by a large value electrolytic capacitor connected across the 70

supply to act as a reservoir, supplying current to the output when the varying 70 voltage

from the rectifier is falling. The diagram shows the unsmoothed varying 70 dotted

line< and the smoothed 70 solid line


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!moothing ca"acitor for #$% ri""le& C '

0 G smoothing capacitance in farads F<

o G output current from the supply in amps A<

6s G supply voltage in volts 6


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Voltage Regulator:

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6oltage regulator 0s are available with fi2ed typically $, B% and B$6< or variable

output voltages. They are also rated by the ma2imum current they can pass. 4egative

voltage regulators are available, mainly for use in dual supplies. Most regulators include

some automatic protection from e2cessive current =overload protection=< and

overheating =thermal protection=


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Zener diode regulator:

For low current power supplies a simple voltage regulator can be made with a resistor

and a *ener diode connected '$ %#v#%(# as shown in the diagram. &ener diodes are rated

by their 0%#!1,ow$ vol !"# 2 and )!4')+) ow#% P typically - m' or B.?'


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$. The %#('( o% %#('( !$ #3 R G 6s ( 6*< K ma2

. The %#('( o% ow#% %! '$"3 9 J 6s ( 6*< E ma2

5.MICRO CONTROLLER A )' %o o$ %oll#% or MCU < is a computer(on(a(chip used to control electronic

devices. t is a type of microprocessor emphasi*ing self(sufficiency and cost(

effectiveness, in contrast to a general(purpose microprocessor the 1ind used in a 90


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A typical mid range vehicle has as many as $ or more microcontrollers. They can also

be found in almost any electrical device3 washing machines, microwave ovens,

telephones etc

T!0l# 5.6 8ome of the commonly used microcontrollers.

-(bit

Microcontrollers

Te2as nstruments TM8 B

4ational 0)9-%

Iitachi IM08-

Toshiba T!08-C

"(bit

Microcontrollers

ntel " -"

ntel " $B

Microchip 9 0B 0$

4ational 0)9"%

Motorola "I0BB

Te2as nstruments TM8C$

&ilog &"

B (bit

Microntrollers

Motorola M0 "??%

ntel M08(# Family of Microcontrollers includes

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" # DI, " 0B# D, and " 0B# 0<

Motorola "I0B

4ational I90B B -

Iitachi I"K$?%

?%(bit

Microcontrollers

ntel " # 0A, A, D, M0

!R ??

AM7 Am%# $

48 ?%

A microcontroller contains a complete central processing unit 09@< along with a

full complement of interfacing peripherals. The complete range of binary inputKoutput,

both parallel and serial, and synchronous and asynchronous is available on most of the

microcontrollers. The objective is to ma1e the microcontrollers not primarily message

handlers but to allow effective communication with other similar devices. )ne of the

important features of a microcontroller is the on(chip analog(to(digital converter A70


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Another important feature of a microcontroller is the availability of on(chip

timers. Most microcontrollers have versatile timers that can be configured in real time.

These timers can be reprogrammed as to the duration of time that they will measure, the

type of interrupt that they will generate, and whether they will reload and continue to

time the ne2t time period automatically. A second type of timer called a watchdog timer

is also usually available on(chip. This timer is used to restart the microcontroller if it

fails to be reset at regular intervals. The interval between clearing the watchdog timer is

usually programmable and is chosen to fit the type of application.

Microcontrollers are available with different types and amounts of on(chip

memories. For e2ample, ntel " 0B# D has " 1ilobytes of on(chip 9R)M and %?%

bytes of on(chip RAM while ntel " 0B# 0 has B 1ilobytes of 9R)M and -""

bytes of on(chip RAM. )nly a small amount of on(chip RAM is provided because

microcontrollers usually compute transient 5uantities; they are not meant to be word

processors.

A functioning microcontroller system re5uires only e2ternal R8%?% voltage

converters and a crystal oscillator. Iowever, a microcontroller system used for comple2

applications may include e2ternal memory.

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B!(' ( %+ +%# o/ ! )' %o o$ %oll#%

Figure shows the bloc1 diagram of a typical microcontroller. The four basic parts

of a microcontroller are3 central processing unit 09@


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The 09@ of a microcontroller consists of arithmetic and logic unit A!@


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code and operand s


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information stored in memory, it is performing a read operation. 'hen the 09@ sends

information to be stored in the memory, it is performing a write operation. Memory is

classified as internal and e2ternal memory. nternal memory is on(chip memory and is a

semiconductor type with low capacity and high speeds. 2ternal memory is outside the

chip and includes the semiconductor type and serial memory such as magnetic dis1s,

magnetic tapes, and bubble memory. 8emiconductor memory may be volatile or

nonvolatile. 6olatile memory loses its contents after the power is removed from the

memory chip. 4onvolatile memory does not lose its contents when power is removed.

The nonvolatile memory can store information permanently or at least semi(permanently

ten years or more


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The storage cell of a R)M Read(only memory< consists of a DOT Dipolar

Ounction Transistor


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7.MICROCONTROLLER AT89S ;

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F'"7.6 :A% *' # +%# o/ 89S ;

F AT@R 83

0ompatible with M08($B 9roducts.

" Dytes of n(8ystem Reprogrammable Flash Memory.ndurance3 B, 'riteK rase 0ycles.

QFully 8tatic )peration3 I* to %- MI*.Three(level 9rogram Memory !oc1.%$ 2 "(Dit nternal RAM.?% 9rogrammable K) !ines.Three B (bit TimerK0ounters.

ight nterrupt 8ources.9rogrammable 8erial 0hannel.

!ow 9ower dle and 9ower 7own Modes

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9 4 7 A+RAM A47 T8 7 80R 9T )43

The microcontroller generic part number actually includes a whole family of

microcontrollers that have numbers ranging from " ?Bto "C$B and are available in 4(

0hannel Metal )2ide 8ilicon 4M)8< and 0omplementary Metal )2ide 8ilicon

0M)8< construction in a variety of pac1age types.

PIN DIAGRAM

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F'"7.; : P'$ D'!"%!)

'ith - bytes of Flash 9rogrammable and rasable Read )nly Memory

9 R)M


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with Flash on a monolithic chip, the Atmel AT"#8$% is a powerful microcomputer which

provides a highly fle2ible and cost effective solution to many embedded control

applications.

The AT"#8$% provides the following standard features3 - bytes of Flash, %$

bytes of RAM, ?% K) lines, two B (bit timerKcounters, five vector two(level interrupt

architecture, a full duple2 serial port, on(chip oscillator and cloc1 circuitry. n addition,

the AT"#8$% is designed with static logic for operation down to *ero fre5uency and

supports two software selectable power saving modes. The dle Mode stops the 09@

while allowing the RAM, timerKcounters, serial port and interrupt system to continue

functioning. The 9ower down Mode saves the RAM contents but free*es the oscillator

disabling all other chip functions until the ne2t hardware reset.

Po%


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Po% 6:9ort B is an "(bit bi(directional K) port with internal pull(ups. The 9ort B output

buffers can sin1Ksource four TT! inputs. 'hen Bs are written to 9ort B pins they are

pulled high by the internal pull(ups and can be used as inputs. As inputs, 9ort B pins that

are e2ternally being pulled low will source current !< because of the internal pull(ups.

9ort B also receives the low(order address bytes during Flash programming and program

verification.

Alternate functions of port 1

Po% ;:

9ort % is an "(bit bidirectional K) port with internal pullups. The 9ort % output

buffers can sin1Ksource four TT! inputs. 'hen Bs are written to 9ort % pins they are

pulled high by the internal pull(ups and can be used as inputs. As inputs, 9ort % pins that

are e2ternally being pulled low will source current !< because of the internal

pullups.9ort % emits the high(order address byte during fetches from e2ternal program

memory and during accesses to e2ternal data memory that use B (bit addresses M)6Page32

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A,S79TR


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wea1ly pulled high. 8etting the A! (disable bit has no effect if the microcontroller is in

e2ternal e2ecution mode.

98 43

9rogram 8tore nable is the read strobe to e2ternal program memory. 'hen the

AT"#0$% is e2ecuting code from e2ternal program memory, 98 4 is activated twice

each machine cycle, e2cept that two 98 4 activations are s1ipped during each access to

e2ternal data memory.

AK6993

2ternal Access nable. A must be strapped to +47 in order to enable the

device to fetch code from e2ternal program memory locations starting at ))))I up to

FFFFI. 4ote, however, that if loc1 bit B is programmed, A will be internally latched

on reset. A should be strapped to 6cc for internal program e2ecutions. This pin also

receives the B%(volt programming enable voltage 6pp< during Flash programming, for

parts that re5uire B%(volt 6pp.

=TAL6: nput to the inverting oscillator amplifier and input to the internal cloc1

operating circuit

=TAL;: )utput from the inverting oscillator amplifier.

T;: 2ternal count input to TimerK0ounter %, 0loc1 out.Page35

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T% 3 0ounter % captureKreload trigger direction control.

THE ON-CHIP OSCILLATORS

9ins TA!B and TA!% are provided for connecting a resonant networ1 to form

an oscillator. The crystal fre5uency is basic internal cloc1 fre5uency. The ma2imum and

minimum fre5uencies are specified from Bto %-MI&.

9rogram instructions may re5uire one, two or four machine cycles to be e2ecuteddepending on type of instructions. To calculate the time any particular instructions will

ta1e to be e2ecuted, the number of cycles U0N,

T G 0VB%d K 0rystal fre5uency

Iere, we chose fre5uency as BB. $#%MI&. This is because,

DaudG %Vcloc1 fre5uencyK ?%d. B%dW%$ d(TIBX


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O$-C*' O( 'll! o%(

9rogram Memory !oc1 Dits3

)n the chip there are three loc1 bits which can be left un programmed @< or can

be programmed 9< to obtain the additional features .'hen loc1 bit B is programmed, the

logic level at the A pin is sampled and latched during reset. f the device is powered up

without a reset, the latch initiali*es to a random value, and holds that value until reset is

activated. t is necessary that the latched value of A be in agreement with the current

logic level at that pin in order for the device to function properly.

9rogram 0ounter and 7ata 9ointer3

The "#0$% contains two B (bit registers3 the program counters 90< and the data

pointer 79TR


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program instructions and can be specified by its B (bit name, 79TR, or by each

individual byte name, 79I and 79!. 79TR does not have a single internal address;

79I and 79! are each assigned an address.

A D Registers3

The "#0$% contains ?- general(purpose, wor1ing, registers. Two of these,

registers A and D, hold results of many instructions, particularly math and logical

operations, of the "#0$% 09@. The other ?% are arranged as part of internal RAM in

four ban1s, D (D?, of eight registers. The A register is also used for all data transfers

between the "#0$% and any e2ternal memory. The D register is used for with the A

register for multiplication and division operations.

Flags and the 9rogram 8tatus 'ord 98'


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89 0 A! F@40T )4 R + 8T R83

The "#8$% operations that do not use the internal B%"(byte RAM addresses from

h to CFh are done by a group of specific internal registers, each called a 8pecial

Function register, which may be addressed much li1e internal RAM, using addresses

from " h to FFI. 90 is not part of the 8FR and has no internal RAM address

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TABLE 7.6

8.CIRCUIT DIAGRAM OF TRANSMITTER

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FIG 8.6

CIRCUIT DIAGRAM >RECEI2ER?

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FIG 8.;

9. ; P'$ Co) o$#$ H+)',' & S#$(o%

A % pin sensor which is designed to measure relative humidity up to # H.The

operation of the sensor is simple,the impedance across the two terminals decreases as

humidity increases.Typical applications include air conditioners and purifiers,weather

stations and data loggers.

.

SPECIFICATION:

0 R$!ed ol!$ge# #VPage43

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0 R$!ed Power# $.+m,

0 Oper$!i&g Fre2ue& y R$&ge# 5$$- to

+&$$$-

0 Oper$!i&g e per$!ure R$&ge# $ /C to01$ /C

0 Oper$!i&g u idi!y R$&ge# 2" to 3$% 4-

0 u idi!y A ur$ y# 5%

FIG 9.6 HUMIDITY SENSOR

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6FIG 6


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The two copper leads act as the sensor probes. They are immersed into thespecimen soil whose moisture content is under test. The soil is e2amined under threeconditions

6 C!(#@6: D%& o$,' 'o$ 3 The probes are placed in the soil under dry conditions

and are inserted up to a fair depth of the soil. As there is no conduction path between the two copper leads the sensor circuit remains open. The voltage outputof the emitter in this case ranges from to .$6.

6 C!(#@;: O ')+) o$,' 'o$ ( 'hen water is added to the soil, it percolatesthrough the successive layers of it and spreads across the layers of soil due tocapillary force. This water increases the moisture content of the soil. This leads toan increase in its conductivity which forms a conductive path between the twosensor probes leading to a close path for the current flowing from the supply to

the transistor through the sensor probes. The voltage output of the circuit ta1en atthe emitter of the transistor in the optimum case ranges from B.# to ?.-6appro2imately.

6 C!(#@3: E4 #(( w! #% o$,' 'o$ ( 'ith the increase in water content beyond theoptimum level, the conductivity of the soil increases drastically and a steadyconduction path is established between the two sensor leads and the voltageoutput from the sensor increases no further beyond a certain limit. The ma2imum

possible value for it is not more than -.%6.

11.R !"#:

A relay is an #l# %' !ll& o #%! #, (w' *. 0urrent flowing through the coil of the relay

creates a magnetic field which attracts a lever and changes the switch contacts. The coil

current can be on or off so relays have two switch positions and they are ,o+0l# *%ow

*!$"#ov#% < switches.

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Relays allow one circuit to switch a second circuit which can be completely separate

from the first. For e2ample a low voltage battery circuit can use a relay to switch a %? 6

A0 mains circuit. There is no electrical connection inside the relay between the two

circuits, the lin1 is magnetic and mechanical.

The coil of a relay passes a relatively large current, typically ? mA for a B%6 relay, but

it can be as much as B mA for relays designed to operate from lower voltages. Most

0s chips< cannot provide this current and a transistor is usually used to amplify the

small 0 current to the larger value re5uired for the relay coil. The ma2imum output

current for the popular $$$ timer 0 is % mA so these devices can supply relay coils

directly without amplification.

Relays are usuallly 897T or 797T but they can have many more sets of switch

contacts, for e2ample relays with - sets of changeover contacts are readily available. For

further information about switch contacts and the terms used to describe them please see

the page on switches .

Most relays are designed for 90D mounting but you can solder wires directly to the pins

providing you ta1e care to avoid melting the plastic case of the relay.

The supplier=s catalogue should show you the relay=s connections. The coil will be

obvious and it may be connected either way round. Relay coils produce brief high

voltage =spi1es= when they are switched off and this can destroy transistors and 0s in the

circuit. To prevent damage you must connect a protection diode across the relay coil.

The animated picture shows a wor1ing relay with its coil and switch contacts. You can

see a lever on the left being attracted by magnetism when the coil is switched on. This

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lever moves the switch contacts. There is one set of contacts 897T< in the foreground

and another behind them, ma1ing the relay 797T.

The relay=s switch connections are usually labelled 0)M, 40 and 4)3

• COM G 0ommon, always connect to this, it is the moving part of the switch.

• NC G 4ormally 0losed, 0)M is connected to this when the relay coil is o// .

• NO G 4ormally )pen, 0)M is connected to this when the relay coil is o$ .

• 0onnect to 0)M and 4) if you want the switched circuit to be o$ w*#$ *#

%#l!& o'l '( o$ .

• 0onnect to 0)M and 40 if you want the switched circuit to be o$ w*#$ *#

%#l!& o'l '( o// .

CLASSIFICAION OF PROTECTI2E RELAYS BASED ON TECHNOLOGY

9rotective relays can be broadly classified into the following categories

B. lectromagneticrelays

%.8taticrelays

?.Microprocessor(basedrelays

El# %o)!"$# ' %#l!&( 3

t includes attracted armature, moving coil and induction disc and

induction cup type relays. lectromagnetic relays contain an electromagnet or

permanent magnet< and a moving part. 'hen the actuating 5uantity e2ceeds a certain

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predetermined value, an operating tor5ue is developed which is applied on the moving

part. This causes the moving part to travel and to finally close a contact to energi*e the

tripcoilofthebre*a1er.

S ! ' %#l!&(:- 8tatic relays contains electronic circuits which may contain

transistors, 0s, diodes and other electronic components. There is a comparator circuit in

the relay, which compares two or more voltages and gives an output, which is applied to

either a slave Zready or a thyristor circuit. The slave ready is an electromagnetic relay

which finally ;closes the contact. A static relay containing a slave ready is semi(static

relay. A relay 1ising thyristor circuit is a wholly static relay. 8tatic relay possess the

advantage of having ilow burden on 0T and 9T, fast operation, absence of mechanical

inertia and contact trouble, long life and less maintenance. 8tatic relays have proved to

be superior to electromagnetic relays and they are being used for the protection of

important lines, power stations and substations. Yet they have not completely replaced

electromagnetic relays. 8tatic relays are treated as an addition to family of relays.

lectromagnetic relays continue to be in use because of their simplicity and low cost.

Their maintenance can be done by less 5ualified personal, where as the maintenance and

repair of static relays re5uires personnel=s trained in solid(state

M' %o %o #((o%-0!(#, %o # 'v#%#l!&( -

Microprocessor(based protective relays are the latest

development in this area. 'ith the development in 6!8 Technology, 8ophisticated and

fast microprocessor are coming up. Their applications to the problems of protectiverelaying schemes are of current interests to power engineers. The inherit advantages of

microprocessor(based relays over static relays with or a very limited range of

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Microprocessor(based protective relays can provide protection at low cost and compete

with conventional relays. The present downward trend in the cost of large(scale

integrated circuit will encourage wide applications of microprocessor(based applications

of microprocessor(based relays for the protection modem comple2 power networ1.

Fig 11.1 R*LA, CIRC+I /

A,v!$ !"#( o/ %#l!&(:Page50

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• Relays can switch AC !$, DC , transistors can only switch 70.

• Relays can switch *'"* vol !"#( , transistors cannot.

•

Relays are a better choice for switching l!%"# +%%#$ ( J $A


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9ifferential analog voltage in"uts:ogic in"uts an out"uts meet both ;! an TT: voltage level s"ecifications,or*s with +.5V (:


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FIG 12.2-ADC 0804

13.MAX232

The MAX232 IC is used to convert the TTL/CMOS lo ic levels to !S232 lo ic levels durin

seri"l co##unic"tion o$ #icrocontrollers %ith PC& The controller o'er"tes "t TTL lo ic

level ()*+,- %here"s the seri"l co##unic"tion in PC %or.s on !S232 st"nd"rds (*2+ , to

2+,-& This #".es it di0cult to est"1lish " direct lin. 1et%een the# to co##unic"te

%ith e"ch other&

The inter#edi"te lin. is 'rovided throu h MAX232& It is " du"l driver/receiver th"t

includes " c"'"citive volt" e ener"tor to su''l !S232 volt" e levels $ro# " sin le +,

su''l & E"ch receiver converts !S232 in'uts to +, TTL/CMOS levels& These receivers (! 4

! 2- c"n "cce't 53), in'uts& The drivers (T 4 T 2-6 "lso c"lled tr"ns#itters6 convert the

TTL/CMOS in'ut level into !S232 level&

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The tr"ns#itters t".e in'ut $ro# controller7s seri"l tr"ns#ission 'in "nd send the out'ut

to !S2327s receiver& The receivers6 on the other h"nd6 t".e in'ut $ro# tr"ns#ission 'in o$

!S232 seri"l 'ort "nd ive seri"l out'ut to #icrocontroller7s receiver 'in& MAX232 needs

$our e8tern"l c"'"citors %hose v"lue r"n es $ro# 9F to 229F&

M !"#!#$%"#&&e" MAX232 RS232

T8 T /2 In T /2 Out !8

!8 ! /2 Out ! /2 In T8

P'$ D'!"%!):

FIG 13.1

P $ De'!" (% #$)

P $ F*$!% #$ +a,e

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+#

C"'"citor connection 'ins

C"'"citor 2 C"'"citor 3 3 C"'"citor *: C"'"citor 2 + C"'"citor 2 *

; C"'"citor : *< Out'ut 'in= out'uts the seri"ll tr"ns#itted d"t" "t !S232

lo ic level= connected to receiver 'in o$ PC seri"l 'ort T 2 Out

> In'ut 'in= receives seri"ll tr"ns#itted d"t" "t !S 232lo ic level= connected to tr"ns#itter 'in o$ PC seri"l 'ort

! 2 In

? Out'ut 'in= out'uts the seri"ll tr"ns#itted d"t" "t TTLlo ic level= connected to receiver 'in o$ controller&

! 2 Out

) In'ut 'ins= receive the seri"l d"t" "t TTL lo ic level=connected to seri"l tr"ns#itter 'in o$ controller&

T 2 InT In

2 Out'ut 'in= out'uts the seri"ll tr"ns#itted d"t" "t TTLlo ic level= connected to receiver 'in o$ controller&

! Out

3 In'ut 'in= receives seri"ll tr"ns#itted d"t" "t !S 232lo ic level= connected to tr"ns#itter 'in o$ PC seri"l 'ort

! In

: Out'ut 'in= out'uts the seri"ll tr"ns#itted d"t" "t !S232lo ic level= connected to receiver 'in o$ PC seri"l 'ort

T Out

+ @round (),- @round; Su''l volt" e= +, (:&+, +&+,- ,cc

TABLE 13.1

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FIG 13.8

14.I6 *RFACI6G LCD O * MICROCO6 ROLL*R

This is the first interfacing e am"le for the "arallel "ort. ,e will star with somethingsim"le. This e am"le oes not use the Bi= irectional feature foun on newer "orts& thus it shoul wor*with most& if no all arallel orts. It however oes not show the use of the status "ort as an in"ut. !owhat are we interfacingD A #1 Character + :ine :C9 o ule to the "arallel "ort. These :C9

o ules are very common these ays& an are @uite sim"le to wor* with& as all the logic re@uire

running them is on boar .

FeaturesG

Interface with either H=bit or 7=bit micro"rocessor.

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9is"lay ata 4A

7 bits (7$ characters). 7$

Character generator 4;

J ot=matri character "atterns. #1$ ifferent 5

Character generator 4A

J ot=matri "atterns. 7 ifferent users "rogramme 5

9is"lay ata 4A an character generator 4A may be

Accesse by the micro"rocessor.

>umerous instructions

Clear 9is"lay& Cursor -ome& 9is"lay ;>K;FF& Cursor

;>K;FF& Blin* Character& Cursor !hift& 9is"lay !hift.

Built=in reset circuit is triggere at "ower ;>.

A general "ur"ose al"hanumeric :C9& with two lines of #1 characters.

FIG 14.1

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Pi& di$gr$ # FIG-14.8/

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ABL* 14.1

In the above table Vcc an Vss are su""ly "ins an VEE ( in no.o.H is 4s "in for selecting the register& there are two very im"ortant registers are therein si e the :C9. The 4! "in is use for their selection as follows. If 4!'$& the instruction commanco e register is selecte & allowing the user to sen ata to be is"laye on the :C9. 4K, is a rea or writes in& which allows the user to write information to the :C9 or rea information from it. 4K,'#when rea ing 4K,'$ when writing. The :C9 to latch information "resente to its ata "ins uses theenable (E) "in. The 7=bit ata "ins& 9$=9J& are use to sen information to the :C9 or rea thecontents of the :C9Ls internal registers. To is"lay letters an numbers& we must sen A!CII co es for the letters A=M& an number $ =3 to these "ins while ma*ing 4!'#.

AB!;:2TE A I 2 4ATI>N!G

#. ELECTRICAL ABSOLUTE MAXIMUM RATINGS G

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9u$li!y o&!rol G

!ome :C9 "anels have efective transistors& causing "ermanently lit or unlit "i elswhich are commonly referre to as stuc* "i els or ea "i els res"ectively. 2nli*e integrate circuits(ICs)& :C9 "anels with a few efective "i els are usually still usable. It is also economically "rohibitive

to iscar a "anel with ?ust a few efective "i els because :C9 "anels are much larger than ICs.

Color di5pl$y5 G

In color :C9s each in ivi ual "i el is ivi e into three cells& or sub "i els& which arecolore re & green& an blue& res"ectively& by a itional filters ("igment filters& ye filters an mo i e filters). Each sub "i el can be controlle in e"en ently to yiel thousan s or millions of "ossible

colors for each "i el. C4T monitors em"loy a similar 8sub "i el8 structures via "hos"hors& although theanalog electron beam em"loye in C4Ts o not hit e act 8sub "i els8.

Color com"onents may be arraye in various "i el geometries& e"en ing on themonitor8s usage. If software *nows which ty"e of geometry is being use in a given :C9& this can beuse to increase the a""arent resolution of the monitor through sub "i el ren ering. This techni@ue ises"ecially useful for te t anti=aliasing.

To re uce smu ging in a moving "icture when "i els o not res"on @uic*ly enough to

color changes& so=calle "i el over rive may be use .

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15. C MP +E+T DESCRIPTI +

TRANSISTOR: -

A transistor consists of two junctions formed by sandwiching either p(type or n(

type semiconductor between a pair of opposite types. Accordingly, there are two types of

transistors namely3 (

B< n(p(n transistor %< p(n(p transistor

>NPN? >PNP?

An n(p(n transistor is composed of two n(type semiconductors separated by a thin

section of p type. Iowever a p(n(p transistor is formed by two p sections separated by a

thin section of n(type. n each type of transistor the following points may be noted.

B. There are two p(n junctions, therefore a transistor may be regarded as

combination of two diodes connected bac1 to bac1.

%. There are three terminals ta1en from each type of semiconductor.

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?. The middle section is a very thin layer, which is the most important factor in the

functioning of a transistor.

-. Transistor can be used as an Amplifier also.

A transistor raises the strength of a wea1 signal and thus acts as an amplifier. The

wea1 signal is applied between emitter base junction and output is ta1en across the load

Rc connected in the collector circuit in common emitter configuration


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during the transformation. Transformers play a major role in the transmission and

distribution of ac power.

P%'$ ' l#: (

Transformer wor1s on the principle of mutual induction. A transformer consists of

laminated magnetic core forming the magnetic frame. 9rimary and secondary coils are

wound upon the two cores of the magnetic frame, lin1ed by the common magnetic flu2.

'hen an alternating voltage is applied across the primary coil, a current flows in the

primary coil producing magnetic flu2 in the transformer core. This flu2 induces voltage

in secondary coil.

Transformers are classified as3 (

a< Dased on position of the windings with respect to core i.e.

B< 0ore type transformer

%< 8hell type transformer

b< Transformation ratio3

B< 8tep up transformer

%< 8tep down transformer

a< 0ore shell types3 Transformer is simplest electrical machine, which consists of

windings on the laminated magnetic core. There are two possibilities of putting

up the windings on the core.

B< 'inding encircle the core in the case of core type transformer

%< 0ores encircle the windings on shell type transformer.

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b< 8tep up and 8tep down3 n these 6oltage transformation ta1es place according to

whether the

9rimary is high voltage coil or a low voltage coil.

B< !ower to higher(J 8tep up%< Iigher to lower(J 8tep down

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1 !P!C!"! MA#U$AC%U&I#' P&OC SS

t is an important process in the fabrication of electronic e5uipment. The design of 90Ds

9rinted 0ircuit Doards< depends on circuit re5uirements li1e noise immunity, wor1ing

fre5uency and voltage levels etc. Iigh power 90Ds re5uire a special design strategy.

The fabrication process to the printed circuit board will determine to a large e2tent

the price and reliability of the e5uipment. A common target aimed is the fabrication of

small series of highly reliable professional 5uality 90Ds with low investment. The target

becomes especially important for customer tailored e5uipments in the area of industrial

electronics.

The layout of a 90D has to incorporate all the information of the board before one can

go on the artwor1 preparation. This means that a concept which clearly defines all the

details of the circuit and partly defines the final e5uipment, is prere5uisite before the

actual lay out can start. The detailed circuit diagram is very important for the layout

designer but he must also be familiar with the design concept and with the philosophy

behind the e5uipment.

BOARD TYPES 3

The two most popular 90D types are3

S'$"l# S',#, Bo!%,(

The single sided 90Ds are mostly used in entertainment electronics where

manufacturing costs have to be 1ept at a minimum. Iowever in industrial electronics

cost factors cannot be neglected and single sided boards should be used wherever a particular circuit can be accommodated on such boards.

Do+0l# S',#, Bo!%,(

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7ouble(sided 90Ds can be made with or without plated through holes. The production

of boards with plated through holes is fairly e2pensive. Therefore plated through hole

boards are only chosen where the circuit comple2ities and density of components does

not leave any other choice.

DESIGN SPECIFICATION

STEPS TAKEN HILE PREPARING CIRCUIT

>A? PCB DESIGNING

The main purpose of printed circuit is in the routing of electric currents and signal

through a thin copper layer that is bounded firmly to an insulating base material

sometimes called the substrate. This base is manufactured with an integrally bounded

layers of thin copper foil which has to be partly etched or removed to arrive at a pre(

designed pattern to suit the circuit connections or other applications as re5uired.

The term printed circuit board is derived from the original method where a printed

pattern is used as the mas1 over wanted areas of copper. The 90D provides an ideal

baseboard upon which to assemble and hold firmly most of the small components.

From the constructorNs point of view, the main attraction of using 90D is its role as themechanical support for small components. There is less need for complicated and time

consuming metal wor1 of chassis contraception e2cept perhaps in providing the final

enclosure. Most straight forward circuit designs can be easily converted in to printed

wiring layer the thought re5uired to carry out the inversion cab footed high light an

possible error that would otherwise be missed in conventional point to point wiring .The

finished project is usually neater and truly a wor1 of art.

Actual si*e 90D layout for the circuit shown is drawn on the copper board. The board is

then immersed in Fe0l 3 solution for B% hours. n this process only the e2posed copper

portion is etched out by the solution.

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4ow the petrol washes out the paint and the copper layout on 90D is rubbed with a

smooth sand paper slowly and lightly such that only the o2ide layers over the 0u are

removed. 4ow the holes are drilled at the respective places according to component

layout as shown in figure.

>B


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increased width where termination holes are needed. From this aspect, it can become

little tric1y to negotiate the route to connect small transistors.

There are basically two ways of copper interconnection patterns under side the

board. The first is the removal of only the amount of copper necessary to isolate the

junctions of the components to oneanother. The second is to ma1e the interconnection

pattern loo1ing more li1e conventional point wiring by routing uniform width of copper

from component to component.

>C?ETCHING PROCESS:

tching process re5uires the use of chemicals. acid resistant dishes and running water

supply. Ferric chloride is mostly used solution but other etching materials such as

ammonium per sulphate can be used. 4itric acid can be used but in general it is not used

due to poisonous fumes.

The pattern prepared is glued to the copper surface of the board using a late2 type

of adhesive that can be cubed after use. The pattern is laid firmly on the copper using a

very sharp 1nife to cut round the pattern carefully to remove the paper corresponding to

the re5uired copper pattern areas. Then apply the resistant solution, which can be a 1ind

of in1 solution for the purpose of maintaining smooth clean outlines as far as possible.

'hile the board is drying, test all the components.

>D? COMPONENT ASSEMBLY 3 (

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From the greatest variety of electronic components available, which runs into thousands

of different types it is often a perple2ing tas1 to 1now which is right for a given job.

There could be damage such as hairline crac1 on 90D. f there are, then they can be

repaired by soldering a short lin1 of bare copper wire over the affected part.

The most popular method of holding all the items is to bring the wires far apart after

they have been inserted in the appropriate holes. This will hold the component in

position ready for soldering.

8ome components will be considerably larger .8o it is best to start mounting the smallest

first and progressing through to the largest. Defore starting, be certain that no further

drilling is li1ely to be necessary because access may be impossible later.

4e2t will probably be the resistor, small signal diodes or other similar si*e

components. 8ome capacitors are also very small but it would be best to fit these

afterwards. 'hen fitting each group of components mar1 off each one on the circuit as it

is fitted so that if we have to leave the job we 1now where to recommence.

Although transistors and integrated circuits are small items there are good reasons for

leaving the soldering of these until the last step. The main point is that these components

are very sensitive to heat and if subjected to prolonged application of the soldering iron,

they could be internally damaged.

All the components before mounting are rubbed with sand paper so that o2ide layer is

removed from the tips. 4ow they are mounted according to the component layout.

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>E? SOLDERING: -

This is the operation of joining the components with 90D after this operation the circuit

will be ready to use to avoid any damage or fault during this operation following care

must be ta1en.

B. A longer duration contact between soldering iron bit components lead can e2ceed

the temperature rating of device cause partial or total damage of the device. Ience

before soldering we must carefully read the ma2imum soldering temperature

soldering time for device.

%. The wattage of soldering iron should be selected as minimum as permissible for that

soldering place.

?. To protect the devices by lea1age current of iron its bit should be earthed properly.

-.'e should select the soldering wire with proper ratio of 9b Tn to provide the

suitable melting temperature.

$.9roper amount of good 5uality flu2 must be applied on the soldering point to avoid dry

soldering.

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17.Basic Concept-KEIL

$ntroduction

This tutorial will assist you in writing your first " $B Assembly language program usingthe popular eil

0ompiler. eil offers an evaluation pac1age that will allow the assembly and debuggingof files % or less. This

pac1age is freely available at their web site. eilNs website address is www.1eil.com.

The sample program included in the tutorial toggles 9orts B and % on the " $B. Thecompiled program

has been tested using the " $B board from Micro7igital d.com. The program alsowor1s with other systems that

have 9ort B and % available.

Dasic eil Tutorial

B. )pen eil from the 8tart menu

%. The Figure below shows the basic names of the windows referred in this document

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8tarting a new Assembler 9roject

B. 8elect 4ew 9roject from the 9roject Menu.

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%. 4ame the project UToggle.a$BN

?. 0lic1 on the 8ave Dutton.

-. The device window will be displayed.

$. 8elect the part you will be using to test with.

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. 7ouble 0lic1 on the 7allas 8emiconductor.Page74

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C. 8croll down and select the 78"#0-% 9art

". 0lic1 )

0reating 8ource File

B. 0lic1 File Menu and select 4ew.

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%. A new window will open up in the eil 7 .

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?. 0opy the e2ample to the Right into the new window. This file will toggle 9orts B and% with a delay.

-. 0lic1 on File menu and select 8ave As[

)R+ I

M)6 A, \$$I

A+A 43

M)6 9B, A

M)6 9%, A

A0A!! 7 !AY

09! A

8OM9 A+A 4

7 !AY3

M)6 R?, \%

)@T R3 M)6 R%, \ %$$44 R3 7O4& R%, 44 R

7O4& R?, )@T R

R T

47

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$. 4ame the file Toggle.a$B

. 0lic1 the 8ave Dutton

Adding File to the 9roject

B. 2pand Target B in the Tree Menu

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%. 0lic1 on 9roject and select Targets, +roups, Files[

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?. 0lic1 on +roupsKAdd Files tab

-. @nder Available +roups select 8ource +roup B

$. 0lic1 Add Files to +roup[ button

. 0hange file type to Asm 8ource file V.aV;

V.src<

C. 0lic1 on toggle.a$B

". 0lic1 Add button

#. 0lic1 0lose Dutton

B . 0lic1 ) button when you return to Target, +roups, Files[ dialog bo2

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BB. 2pand the 8ource +roup B in the Tree menu to ensure that the file

was added to the project.

0reating I for the 9art

B. 0lic1 on Target B in Tree menu

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%. 0lic1 on 9roject Menu and select )ptions for Target B

?. 8elect Target Tab

-. 0hange tal Mh*< from $ . to BB. $#%

$. 8elect )utput Tab

. 0lic1 on 0reate Ie2 File chec1 bo2

C. 0lic1 ) Dutton

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Testing 9rogram in 7ebugger

B. 0omment out line A0A!! 7 !AY by placing a 8emicolon

at the beginning. This will allow you to see the port change immediately.%. 0lic1 on the File Menu and select 8ave

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?. 0lic1 on 9roject Menu and select Rebuild all Target Files

-. n the Duild 'indow it should report U rrors s


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$. 0lic1 on 7ebug Menu and 8elect 8tartK8top 7ebug 8ession

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Running the eil 7ebugger

B. The eil 7ebugger should be now be Running.

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%. 0lic1 on 9eripherals. 8elect K) 9orts, 8elect 9ort B

?. A new window should port will pop up. This represent the 9ort and 9ins

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-. 8tep through the code by pressing FBB on the eyboard. The 9arallel 9ort B Do2should change you completely step through the code

. To e2it out, 0lic1 on 7ebug Menu and 8elect 8tartK8top 7ebug 8ession

68.ZIGBEE MODULE

Features and Denefits3

oint to "oint& "oint to multi "oint& esh an "eer=to="eer to"ologies on "ro"rietary stac*. 9irect !e@uence !"rea !"ectrum technology.

Each irect se@uence channel has 1HO uni@ue networ* a resses Transmit owerG ++ Bm. 4F ata rateG +5$ *b"s. Ac*nowle gement mo e communication with retries. ower saving mo es. !ource K estination a ressing.

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2nicast an broa cast communication. Analog to igital conversion an igital IK; line su""ort. 9efault configuration for rea y to use.

S # '/' ! 'o$(:

Power !u""ly Voltage I9& Channel an a ressesMe '$&i $l

9imensions


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F'" 68.6

1%.&'D$()

TR"(S*$TT R :

\include]reg$B.hJ

sbit rdG9?^$;

sbit wrG9?^-;

sbit intrG9?^?;

sbit rsG9?^C;

sbit eG9?^ ;

sbit watersensorG9%^ ;

sbit motorG9 ^B; KKconnect pull up B 1

unsigned convert unsigned int


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unsigned int i,j;

for iG ;i]t;i::<

for jG ;j]B%C$;j::


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wrGB;

while B<

_

wrG ;

wrGB;

while intrGGB


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`

if watersensor GG <

_

motorGB;

sert2 =o=


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dGbHB ;

aGa 2? ;

cGc 2? ;

dGd 2? ;

sert2 =V=


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9%Gp;

rsG ;

eGB;

delay $


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unsigned char r2;

while R GG


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lcd dat =3=


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aBGreceive


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SCOPE FO R FURT HER DE 2ELOPMENT

B< The performance of the system can be further improved in terms of the operating

speed, memory capacity, instruction cycle period of the microcontroller.The number

of channels can be increased to interface more number of sensors which is possible

by using advanced versions of

microcontrollers.

%< The system can be modified with the use of a datalogger and a graphical !07

panel showing the measured sensor data over a period of time.

?< This system can be connected to communication devices such as modems, cellular

phones or satellite terminal to enable the remote collection of recorded data or

alarming of certain parameters.

-< The device can be made to perform better by providing the power supply with the

help of battery source which can be rechargeable or non(rechargeable, to reduce the

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$< Time bound administration of fertili*ers, insecticides and pesticides can beintroduced.

< A multi(controller system can be developed that will enable a master controller along with its slave controllers to automate multiple greenhousessimultaneously.

CO NCLUSION

A step(by(step approach in designing the microcontroller based

system for measurement and control of the four essential parameters for plant

growth, i.e. temperature, humidity, soil moisture, and light intensity, has been

followed. The results obtained from the measurement have shown that the system

performance is 5uite reliable and accurate.

The system has successfully overcome 5uite a few shortcomings of the

e2isting systems by reducing the power consumption, maintenance and comple2ity, at

the same time providing a fle2ible and precise form of maintaining the environment.

The continuously decreasing costs of hardware and software, the wider

acceptance of electronic systems in agriculture, and an emerging agricultural control

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system industry in several areas of agricultural production, will result in reliable

control systems that will address several aspects of 5uality and 5uantity of

production. Further improvements will be made as less e2pensive and more reliable

sensors are developed for use in agricultural production.

Although the enhancements mentioned in the previous chapter may seem far in

the future, the re5uired technology and components are available, many such systems

have been independently developed, or are at least tested at a prototype level. Also,

integration of all

these technologies is not a daunting tas1 and can be successfully carried out.

RE FERE NCE S

WBX 7r. R. Oayanthi, 9rof. of Iorticulture, @A8, + 6 , Dangalore.

IEEE P! #%(:

WBX 8tipanicev 7., Marasovic O., Networked embedded greenhouse monitoring andcontrol,

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